Tunable negative Poisson's ratio in hydrogenated graphene

TL;DR

This study uses molecular dynamics simulations to show that hydrogenation can tune graphene's Poisson's ratio from positive to negative, with a minimum of -0.04 at 50% hydrogenation, due to ripple suppression.

Contribution

It reveals a controllable method to switch graphene's Poisson's ratio from positive to negative via hydrogenation, a novel approach in material property tuning.

Findings

Poisson's ratio decreases with hydrogenation percentage

Minimum Poisson's ratio of -0.04 at 50% hydrogenation

Hydrogenation suppresses ripples affecting mechanical response

Abstract

We perform molecular dynamics simulations to investigate the effect of hydrogenation on the Poisson's ratio of graphene. It is found that the value for Poisson's ratio in graphene can be effectively tuned from positive to negative by varying the percentage of hydrogenation. Specifically, the Poisson's ratio decreases with the increase of the percentage of hydrogenation, and reaches a minimum value of -0.04 at the percentage of hydrogenation about 50%. The Poisson's ratio starts to increase with a further increase of the percentage of hydrogenation. The appearance of minimum negative Poisson's ratio in the hydrogenated graphene is attributed to the suppression of the hydrogenation-induced ripples during stretching of graphene. Our results demonstrate that hydrogenation is a valuable approach for the tuning of the Poisson's ratio from positive to negative in graphene.